Today, on my laptop (Lenovo G510) running Windows 8.1, my Wi-Fi and ethernet capabilities both decided to go kaput with no warning and no obvious way to fix the problem. With the ethernet cord plugged in, my router/modem recognized a LAN connection, but my computer showed nothing. The internal Wi-Fi card was still recognized by the computer, but it was non-functional, and the switch to enable Wi-Fi in Windows settings was disabled and greyed out.
I tried enabling and disabling the network adaptor, rebooting, rebooting in safe mode, and using the built-in troubleshooter (which just told me I needed to toggle a physical switch on my laptop to enable wireless networking, but the laptop has no such switch), all to no avail. Finally, I came across this thread, where a user with my exact same laptop and problem asked for help and was given a solution that worked.
The solution? Unplugging the laptop, taking out the battery, and pressing the power button five times, then putting the battery back in and starting up the computer.
So, skeptical but a little desperate, I tried it, and sure enough, it fixed the problem for me, too.
Now I'm wondering what, exactly, on earth is the technical reason behind that odd solution working for both me and that other person. What does pressing the power button with no power do? Is that something specific to the Lenovo G510 only, or would it do something on other laptops, too?